Many camshaft phasers include a positioning spring that biases a rotor in a circumferential direction with respect to a stator by being connected at one end to the stator and at another end to the rotor. The positioning spring must be retained axially and radially during use in order to remain in its proper position within the camshaft phaser.
For example, U.S. Patent Application Publication No. 2009/0211549 discloses stop members for retaining a pair of spiral springs radially and a spring retention plate for retaining the springs axially. While this configuration retains the spiral spring in position, the use of a spring retention plate, separate from radial stop members, increases the number of components of the camshaft phaser, which increases cost. Further, the spring retention plate increases the size of the camshaft phaser. Due to space restrictions within an engine, it would be advantageous to minimize the size of the camshaft phaser.
Current configurations that do not include a spring retention plate, such as those that use press-fit nail-head pins, include other drawbacks. For example, such nail-head pins require an additional grinding operation in order to precisely size the nail-head pins so that they are reliably held in position when pressed in to the corresponding holes in the camshaft phaser housing. This additional grinding operation introduces additional cost and complexity to the assembly of the camshaft phaser. Furthermore, the nail-head pins are required to carry both bending and shear loads as they are positioned in apertures in the rotor and/or stator to retain the spring, and accordingly must be formed of a high strength, preferably steel, material to carry the loads, which makes the forming process more costly in comparison to straight steel pins, such as bearing needles, which have also been used for radial retention of such springs.
The present disclosure is directed to overcoming one or more problems of the prior art.